The present invention provides nucleotide sequences of coryneform bacteria coding for the sigD gene and a process for the enzymatic production of amino acids using bacteria in which the sigD gene is enhanced. All references cited herein are expressly incorporated by reference. Incorporation by reference is also designated by the term “I.B.R.” following any citation.
L-amino acids are used in human medicine and in the pharmaceutical industry, in the foodstuffs industry and, most especially, in animal nutrition.
It is known that amino acids can be produced by fermentation of strains of coryneform bacteria, in particular Corynebacterium glutamicum. On account of the great importance of amino acids efforts are constantly being made to improve the production processes. Process improvements may involve fermentation technology measures such as for example stirring and provision of oxygen, or the composition of the nutrient media, such as for example the sugar concentration during the fermentation, or the working-up to the product form by for example ion exchange chromatography or the intrinsic performance properties of the microorganism itself.
In order to improve the performance properties of these microorganisms methods involving mutagenesis, selection and mutant selection are employed. In this way strains are obtained that are resistant to antimetabolites or are auxotrophic for regulatorily important metabolites, and that produce amino acids.
For some years methods of recombinant DNA technology have also been used to improve L-amino acid-producing strains of corynebacterium, by amplifying individual amino acid biosynthesis genes and investigating the effect on amino acid production.
The invention provides new techniques for the improved enzymatic production of amino acids.